[DevTools] Migrate TargetObserver to AnimationModel observer where makes sense.

third_party/WebKit/Source/devtools/front_end/animation/AnimationTimeline.js

 // Copyright (c) 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 /**
- * @implements {SDK.TargetManager.Observer}
+ * @implements {SDK.SDKModelObserver<!Animation.AnimationModel>}
  * @unrestricted
  */
 Animation.AnimationTimeline = class extends UI.VBox {
   constructor() {
     super(true);
     this.registerRequiredCSS('animation/animationTimeline.css');
     this.element.classList.add('animations-timeline');
 
     this._grid = this.contentElement.createSVGChild('svg', 'animation-timeline-grid');
 
@@ skipping 10 matching lines @@
     /** @type {!Map.<!Protocol.DOM.BackendNodeId, !Animation.AnimationTimeline.NodeUI>} */
     this._nodesMap = new Map();
     this._uiAnimations = [];
     this._groupBuffer = [];
     /** @type {!Map.<!Animation.AnimationModel.AnimationGroup, !Animation.AnimationGroupPreviewUI>} */
     this._previewMap = new Map();
     this._symbol = Symbol('animationTimeline');
     /** @type {!Map.<string, !Animation.AnimationModel.Animation>} */
     this._animationsMap = new Map();
     SDK.targetManager.addModelListener(SDK.DOMModel, SDK.DOMModel.Events.NodeRemoved, this._nodeRemoved, this);
-    SDK.targetManager.observeTargets(this, SDK.Target.Capability.DOM);
+    SDK.targetManager.observeModels(Animation.AnimationModel, this);
     UI.context.addFlavorChangeListener(SDK.DOMNode, this._nodeChanged, this);
   }
 
   /**
    * @override
    */
   wasShown() {
-    for (var target of SDK.targetManager.targets(SDK.Target.Capability.DOM))
-      this._addEventListeners(target);
+    for (var animationModel of SDK.targetManager.models(Animation.AnimationModel))
+      this._addEventListeners(animationModel);
   }
 
   /**
    * @override
    */
   willHide() {
-    for (var target of SDK.targetManager.targets(SDK.Target.Capability.DOM))
-      this._removeEventListeners(target);
+    for (var animationModel of SDK.targetManager.models(Animation.AnimationModel))
+      this._removeEventListeners(animationModel);
     this._popoverHelper.hidePopover();
   }
 
   /**
    * @override
-   * @param {!SDK.Target} target
+   * @param {!Animation.AnimationModel} animationModel
    */
-  targetAdded(target) {
+  modelAdded(animationModel) {
     if (this.isShowing())
-      this._addEventListeners(target);
+      this._addEventListeners(animationModel);
   }
 
   /**
    * @override
-   * @param {!SDK.Target} target
+   * @param {!Animation.AnimationModel} animationModel
    */
-  targetRemoved(target) {
-    this._removeEventListeners(target);
+  modelRemoved(animationModel) {
+    this._removeEventListeners(animationModel);
   }
 
   /**
-   * @param {!SDK.Target} target
+   * @param {!Animation.AnimationModel} animationModel
    */
-  _addEventListeners(target) {
-    var animationModel = Animation.AnimationModel.fromTarget(target);
+  _addEventListeners(animationModel) {
     animationModel.ensureEnabled();
     animationModel.addEventListener(
         Animation.AnimationModel.Events.AnimationGroupStarted, this._animationGroupStarted, this);
     animationModel.addEventListener(Animation.AnimationModel.Events.ModelReset, this._reset, this);
   }
 
   /**
-   * @param {!SDK.Target} target
+   * @param {!Animation.AnimationModel} animationModel
    */
-  _removeEventListeners(target) {
-    var animationModel = Animation.AnimationModel.fromTarget(target);
+  _removeEventListeners(animationModel) {
     animationModel.removeEventListener(
         Animation.AnimationModel.Events.AnimationGroupStarted, this._animationGroupStarted, this);
     animationModel.removeEventListener(Animation.AnimationModel.Events.ModelReset, this._reset, this);
   }
 
   _nodeChanged() {
     for (var nodeUI of this._nodesMap.values())
       nodeUI._nodeChanged();
   }
 
@@ skipping 111 matching lines @@
     this._pauseButton.setToggled(this._allPaused);
     this._setPlaybackRate(this._playbackRate);
     this._pauseButton.setTitle(this._allPaused ? Common.UIString('Resume all') : Common.UIString('Pause all'));
   }
 
   /**
    * @param {number} playbackRate
    */
   _setPlaybackRate(playbackRate) {
     this._playbackRate = playbackRate;
-    var target = SDK.targetManager.mainTarget();
-    if (target)
-      Animation.AnimationModel.fromTarget(target).setPlaybackRate(this._allPaused ? 0 : this._playbackRate);
+    for (var animationModel of SDK.targetManager.models(Animation.AnimationModel))
+      animationModel.setPlaybackRate(this._allPaused ? 0 : this._playbackRate);
     Host.userMetrics.actionTaken(Host.UserMetrics.Action.AnimationsPlaybackRateChanged);
     if (this._scrubberPlayer)
       this._scrubberPlayer.playbackRate = this._effectivePlaybackRate();
 
     this._updatePlaybackControls();
   }
 
   _updatePlaybackControls() {
     for (var button of this._playbackRateButtons) {
       var selected = this._playbackRate === button.playbackRate;
@@ skipping 499 matching lines @@
   static parse(text) {
     var match = text.match(/^steps\((\d+), (start|middle)\)$/);
     if (match)
       return new Animation.AnimationTimeline.StepTimingFunction(parseInt(match[1], 10), match[2]);
     match = text.match(/^steps\((\d+)\)$/);
     if (match)
       return new Animation.AnimationTimeline.StepTimingFunction(parseInt(match[1], 10), 'end');
     return null;
   }
 };